I was honestly expecting it to start with things like arithmometers (
https://www.youtube.com/watch?v=ppXnnWAssoI), Cooke and Wheatstone 5-needle telegraphs (
https://m.youtube.com/shorts/YKSCqtKZOwg), or perhaps a dictaphone (
https://en.wikipedia.org/wiki/Dictaphone) and what about the rich history of fax machines such as the Pantelegraph (
https://en.m.wikipedia.org/wiki/Pantelegraph). Here's a newspaper being printed by radiofax in the 1930s for instance (
https://commons.m.wikimedia.org/wiki/File:Krant_per_fax_-_Fa...)
Speaking of communications, there's things like Strowger switches (https://m.youtube.com/watch?v=xZePwin92cI&t=111) which I think count because that's what people were interfacing whilst using the phone (this became crossbars and relays in the 1910s and 20s respectively)
Relays and telephone tech btw is how Electro the smoking robot from the 1939 world's fair worked (https://m.youtube.com/watch?v=AuyTRbj8QSA)
Even if we want to limit to computers, we have batch versus time-sharing flow, teletype versus graphical terminals and along those lines you have the work of groups like Evans & Sutherland in the 1970s (such as the line drawing system 1 https://en.wikipedia.org/wiki/LDS-1_(Line_Drawing_System-1) ) or Scientific Data Systems which was later acquired by Xerox. You also have the world of analog computers, the most famous of which is the slide rule.
Even then you can go back to the 19th century Jacquard Loom, which even has a solution to "Hello World" on Rosetta Code (https://rosettacode.org/wiki/Category:Jacquard_Loom)
Then you have specialty machines such as the Fairlight CMI synthesizer with the lightpen interface (https://m.youtube.com/watch?v=iOlPCpSmhRM&t=40) which really laid the groundwork of most DAWs to this day. For music there's lots of things. The theremin which you all know about but also things like Nikolai Voinov's "Paper Sound" https://m.youtube.com/watch?v=Mmejo9WL2gY
You also have 1970s CAD computers, many of which were built by large companies like Mercedes, Nissan, Ford and General Motors (https://www.cadazz.com/cad-software-history-1970s.htm)
Then there's video compositing systems as well such as the lightpen based CMX-600 from 1971: https://www.youtube.com/watch?v=PTUdHncIbq8
The history is way richer then this. Nobody has really given it a good general effort IMHO. Maybe I'm the guy? I hope not. That's a lot of work.